Cable television (CATV) programming has become widely available to the public on a subscription basis. Usually, the subscriber has several levels of service available, with the cost of the subscription dependent upon the options available with each level of service. For example, the basic subscription service usually includes local VHF and UHF programming, which is normally also broadcast for antenna reception throughout the subscription area, and remote VHF and UHF programming from nearby cities, which would not be generally receivable with a local reception antenna at the subscriber premises.
Additional CATV services above the basic service, for example, include movie channels which release the latest movies, and sports channels which make available sporting events normally blacked out from commercial television. However, a subscriber may not customarily obtain a subscription to one or more of these optional services without also obtaining a subscription to the basic service.
The basic subscription service charges are computed from the cost to rebroadcast the local and remote programming and a rental fee for CATV company equipment located at the subscriber premises. Such equipment may include decoders or descramblers for example. The subscription service charges to the optional CATV services includes the right to receive all scheduled programming events provided by the optional service. The subscription charge is based upon the cost to the CATV company to make the service available and the royalties payable to the copyright owners of the programmed events. However, many potential subscribers do not desire to view all scheduled events but merely from time to time desire to view only a selected event, such as a recently released movie or the re-release of an old movie classic. For these viewers the subscription charges of the optional service may be too large to justify the purchase of the subscription for a limited use.
In order to expand the market base of CATV subscribers, there have been several attempts to develop systems wherein a viewer may preselect and only receive an individual programming event. With this type of system the subscriber would not be forced to subscribe to a basic service which he may not desire should normal antenna reception provide adequate service, or be forced to pay the subscription charge for the entire optional service, i.e., paying royalties on all events which the potential subscriber does not wish to view. A CATV system in which the subscriber would only have to pay rental fees for the lease of CATV company equipment and service charges for the events viewed has the potential of expanding the subscriber base of CATV companies.
Two different types of systems have heretofore been developed wherein the subscriber may selectively view a scheduled programming event. In the first group of these systems, the subscriber accesses the CATV computer over phone lines and selects an event from a menu by entering the appropriate data from the telephone key-pad. The menu may either be a recorded voice prompt transmitted through the telephone or a video prompt simultaneously displayed on the subscribers television set. For example, see U.S. Pat. No. 4,381,522 for "Selective Viewing" and U.S. Pat. No. 4,008,369 for a "Telephone Interface Subscription Cable Television System." The second group of systems utilizes an interrogation of a subscriber terminal at the subscriber premises. The subscriber terminal stores information concerning those programs which the subscriber has viewed. The CATV computer interrogates the subscriber terminal over phone lines to retrieve the stored data for billing purposes. For example, see U.S. Pat. No. 4,170,782 and "Pay TV: A Pay per Minute System Prototype", Television: Journal of the Royal Television Society, March 1984, pp. 79-83.
In the above cited '522 patent, there is provided a printed menu of available selectable programs, each designated by a number. The menu is stored in the computer located at the CATV company and broadcast over a menu channel. A viewer at the subscriber premises selects a program by first dialing the CATV station telephone number. The telephone system then connects the viewer's telephone to the CATV computer. The CATV computer responds by transmitting to the viewer an audible tone to signal the viewer to dial the number corresponding to the desired program on the menu. The CATV computer stores the information on the program source location, the status of the selected program source, and the available channels and the schedules for each.
The significant disadvantage and limitation of the system described in the '522 patent is that the CATV Company would require additional information on how to bill the subscriber. Such billing information may only be obtained by additional equipment that would have to be located at the subscriber premises or by requiring the subscriber to input an account number along with the men selection. Such billing information equipment requires additional technical complexity not described in the '522 patent. Accordingly, the '522 patent is described as being most useful for providing video-tex information for the advertisement of products and services. However, where copyrighted material is required, such system does not allow for convenient means for billing the subscriber for service charges.
The above cited '369 patent describes a PABX telephone interface cable television system especially useful in hotels and motels for distributing free and premium program channels via a coaxial cable television signal distribution network to one or more subscriber terminals and associated television sets. Again, the subscriber dials a predetermined access number so that the subscriber can be connected with a control and monitoring station. After a telephone connection is made, the program requests must be subsequently entered through the telephone key-pad. The control and monitoring station includes means for sending output signals to a paper tape printer to provide a record of the channel use activity of each subscriber terminal in the system. Hence, no automatic billing is contemplated in this system, but must be subsequently added to the bill for hotel services.
The above mentioned publication discloses one such automatic billing system wherein a CATV company provided recording device makes a record of the subscriber's usage of the CATV programming events. The recording device, located at the subscriber premises, is periodically interrogated by the CATV company over telephone lines to obtain subscriber usage information necessary to generate a bill to the subscriber. A significant disadvantage and limitation of using a recording device at the subscriber premises is the possibility that the subscriber ma tamper with or bypass the recording device, ultimately resulting in a loss of revenues to the CATV company.